1. Field of the Invention
The invention relates to an air supply apparatus.
2. Description of the Related Art
JP Unexamined Patent Publication (Kokai) No. 2003-336521 discloses an apparatus for warming up a catalyst of an engine. The engine disclosed in the above-mentioned publication comprises two exhaust pipes, and a catalyst is arranged in each exhaust pipe. Further, air is supplied to the catalysts from an air pump in order to increase the temperatures of the catalysts. In the catalysts, a hydrocarbon included in an exhaust gas burns by reacting with the air supplied from the air pump to the catalysts. Thereby, the temperature of each catalyst is increased.
In this connection, it is not preferred to employ a large air pump as the air pump for supplying the air to the catalysts. However, when a small air pump is employed in order to supply the air to a plurality of catalysts, the amount of air supplied by the air pump is insufficient to increase the temperature of each catalyst.
The object of the invention is to provide an air supply apparatus which can supply a large amount of air to the exhaust pipes.